Conventional tufting machines used for the formation of tufted articles such as carpets can include one or more needle bars that carry a plurality of needles arranged in spaced series therealong. Each needle bar typically is driven in a vertically reciprocating manner by a plurality of push rods, which are linked to and thus driven by rotation of a main driveshaft of the tufting machine, so as to reciprocate the needles into and out of a breaking material. The needles carry a series of yarns into the backing material and are engaged by a series of loopers or hooks to form tufts of yarns in the backing material. The needle bar or needle bars further can be shifted laterally with respect to the backing material moving therebelow to provide desired patterning effects and reduce the effects of yarn streaking.
The mounting of a needle bar or needle bars for reciprocation while permitting transverse or lateral shifting movement typically has been accomplished by connection of the needle bar(s) to the push rods by brackets or feet through which the needle bar(s) are slidably received. As a result, as the push rods reciprocate the needle bar(s) vertically, the needle bar(s) further can be shifted or slid laterally though the support feet, which have included ball bearings or bushings in order to facilitate the sliding movement of the needle bar. For example, U.S. Pat. Nos. 4,662,291 and 4,501,212 illustrate prior sliding needle bar drive systems.
The use of such ball bearings or bushings, however, often is limited in terms of the loads they can support, especially at higher machine operating speeds, and further can be subject to increased or more rapid wearing at such increased operating speeds. Advances in production capacity of tufting machines are highly desirable and thus are in demand by the producers or manufacturers of tufted articles such as carpets, as the faster and more efficiently the tufting machines can be run, the more savings in terms of labor and other operational costs can be realized. Currently, conventional tufting machines can be run at upwards of approximately 750 to over 1,300 rpm, and in some cases, in excess of approximately 2,000 rpm. However, at such higher reciprocation/operational speeds, it becomes difficult to accurately control shifting of the needle bars, and the drive systems further can be subjected to increased vibrational forces as well as increased heat and wear due to the effects of the friction between the hardened shafts and ball bearings/bushings traditionally used for guiding the shift rods and push rods of such needle bar drive systems.
Accordingly, it can be seen that a need exists for an improved tufting machine drive system that enables multi-directional movement of operative elements of a tufting machine, such as the reciprocation and lateral shifting or sliding movement of a needle bar of a tufting machine, which addresses the foregoing and other related and unrelated problems in the art.